diff --git a/build.sbt b/build.sbt
index 20b5153f6..d69762670 100644
--- a/build.sbt
+++ b/build.sbt
@@ -4,7 +4,7 @@ import Util._
 def internalPath   = file("internal")
 
 def commonSettings: Seq[Setting[_]] = Seq(
-  scalaVersion := "2.10.5",
+  scalaVersion := scala211,
   // publishArtifact in packageDoc := false,
   resolvers += Resolver.typesafeIvyRepo("releases"),
   resolvers += Resolver.sonatypeRepo("snapshots"),
diff --git a/internal/util-cache/src/main/scala/sbt/internal/util/FileInfo.scala b/internal/util-cache/src/main/scala/sbt/internal/util/FileInfo.scala
index 923f13189..5f7461eae 100644
--- a/internal/util-cache/src/main/scala/sbt/internal/util/FileInfo.scala
+++ b/internal/util-cache/src/main/scala/sbt/internal/util/FileInfo.scala
@@ -8,31 +8,61 @@ import sbinary.{ DefaultProtocol, Format }
 import DefaultProtocol._
 import scala.reflect.Manifest
 import sbt.io.Hash
+import sbt.serialization._
 
 sealed trait FileInfo extends NotNull {
   val file: File
 }
+@directSubclasses(Array(classOf[FileHash], classOf[HashModifiedFileInfo]))
 sealed trait HashFileInfo extends FileInfo {
   val hash: List[Byte]
 }
+object HashFileInfo {
+  implicit val pickler: Pickler[HashFileInfo] with Unpickler[HashFileInfo] = PicklerUnpickler.generate[HashFileInfo]
+}
+@directSubclasses(Array(classOf[FileModified], classOf[HashModifiedFileInfo]))
 sealed trait ModifiedFileInfo extends FileInfo {
   val lastModified: Long
 }
+object ModifiedFileInfo {
+  implicit val pickler: Pickler[ModifiedFileInfo] with Unpickler[ModifiedFileInfo] = PicklerUnpickler.generate[ModifiedFileInfo]
+}
+@directSubclasses(Array(classOf[PlainFile]))
 sealed trait PlainFileInfo extends FileInfo {
   def exists: Boolean
 }
+object PlainFileInfo {
+  implicit val pickler: Pickler[PlainFileInfo] with Unpickler[PlainFileInfo] = PicklerUnpickler.generate[PlainFileInfo]
+}
+@directSubclasses(Array(classOf[FileHashModified]))
 sealed trait HashModifiedFileInfo extends HashFileInfo with ModifiedFileInfo
+object HashModifiedFileInfo {
+  implicit val pickler: Pickler[HashModifiedFileInfo] with Unpickler[HashModifiedFileInfo] = PicklerUnpickler.generate[HashModifiedFileInfo]
+}
 
-private final case class PlainFile(file: File, exists: Boolean) extends PlainFileInfo
-private final case class FileHash(file: File, hash: List[Byte]) extends HashFileInfo
-private final case class FileModified(file: File, lastModified: Long) extends ModifiedFileInfo
-private final case class FileHashModified(file: File, hash: List[Byte], lastModified: Long) extends HashModifiedFileInfo
+private[sbt] final case class PlainFile(file: File, exists: Boolean) extends PlainFileInfo
+private[sbt] object PlainFile {
+  implicit val pickler: Pickler[PlainFile] with Unpickler[PlainFile] = PicklerUnpickler.generate[PlainFile]
+}
+private[sbt] final case class FileHash(file: File, hash: List[Byte]) extends HashFileInfo
+private[sbt] object FileHash {
+  implicit val pickler: Pickler[FileHash] with Unpickler[FileHash] = PicklerUnpickler.generate[FileHash]
+}
+private[sbt] final case class FileModified(file: File, lastModified: Long) extends ModifiedFileInfo
+private[sbt] object FileModified {
+  implicit val pickler: Pickler[FileModified] with Unpickler[FileModified] = PicklerUnpickler.generate[FileModified]
+}
+private[sbt] final case class FileHashModified(file: File, hash: List[Byte], lastModified: Long) extends HashModifiedFileInfo
+private[sbt] object FileHashModified {
+  implicit val pickler: Pickler[FileHashModified] with Unpickler[FileHashModified] = PicklerUnpickler.generate[FileHashModified]
+}
 
 object FileInfo {
   implicit def existsInputCache: InputCache[PlainFileInfo] = exists.infoInputCache
   implicit def modifiedInputCache: InputCache[ModifiedFileInfo] = lastModified.infoInputCache
   implicit def hashInputCache: InputCache[HashFileInfo] = hash.infoInputCache
   implicit def fullInputCache: InputCache[HashModifiedFileInfo] = full.infoInputCache
+  implicit val pickler: Pickler[FileInfo] with Unpickler[FileInfo] = PicklerUnpickler.generate[FileInfo]
 
   sealed trait Style {
     type F <: FileInfo